PURPOSE: To improve a diode element characteristic by connecting two pairs of external leads to be faced to two pairs of electrodes on an insulator, connecting one pair of the electrodes among the two pairs by means of a diode and a fine metallic line, mounting and connecting a capacitor to one side of the pair of the electrodes, and connecting the counter electrode of the capacitor to the electrode pair of the other side.

CONSTITUTION: When an input power is made sufficiently large and a current flows to a PIN diode 1, the resistance of the diode is lowered, and it is considered to be a short circuit. At such a time, when a capacitor 2 of a capacity C1 to generate a serial resonance with an L1 to a signal frequency is inserted in series to the L1. Since an impedance to see the diode from an input port is made into the short circuit, a total reflection is executed. When the input power is sufficiently small, the PIN diode 1 is made into a high resistance, and a signal is transmitted from a line 12 to a line 13. One part of the signal flows into the side of the diode element 1. In order to prevent it, a parallel resonance with the capacity in a diode vicinity is made to occur by the circuit of an inductance L3 and a capacitance C2. Thus, a high impedance can be realized, and losses can be reduced.